THREAD-ROLLING FASTENING PART Russian patent published in 2002 - IPC

FIELD: rod-type fastening parts, thread-forming tapping screws, bolts and studs forming metric thread in smooth holes. SUBSTANCE: thread-rolling self-locking fastening part has thread-forming rod which has form of curvilinear trihedral or pentahedron in cross section with arched sides and vertices and different radii. Radius of arched vertices of curvilinear trihedral or pentahedron is found from the following relationship: r = 0.39-0.50D_cire, where r is radius of arch of arched generatrix of vertex of trihedral or pentahedron; D_cire is diameter of circumscribed circle. Radius of arches of arched sides of trihedral or pentahedron is found from the following relationship: R≥0.59D_cire, where R is radius of arch of arched generatrix of side of curvilinear trihedral or pentahedron. EFFECT: enhanced reliability and resistance of threaded joint; increased contact area; improved locking properties of rod. 2 cl, 3 dwg